Fuel pump

ABSTRACT

A side feed fuel pump with a tube for fixing a fuel filter is developed in that the tube is formed as a portion of an overall housing for jointly enclosing a pump section and a motor section for driving the pump section. The tube that projects laterally from the side feed fuel pump is formed of the overall housing that jointly encloses both the pump section and the motor section. Inner space of the tube forms an intake port, and the intake port communicates a side intake passage formed in the pump casing with an exterior of the fuel pump. A fuel filter can be easily attached to the tube. The tube may be formed by pressing metal plate or integrally molded with a main portion of the overall housing by resin material.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2003-344597, filed on Oct. 2, 2003, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel pump for sucking in fuel, increasing the pressure thereof, and discharging the pressurized fuel.

2. Description of Related Art

A fuel pump that has an impeller and a pump casing is set forth in Japanese Examined Patent Publication 46-33853 and Japanese Unexamined Patent Publication 2000-527677.

The impeller is formed in a substantially disk-like shape and has a plurality of recesses formed in an upper face and a lower face along an outer peripheral region of the disk-like impeller. These recesses are repeated in the circumference direction. The pump casing has an inner lower face and an inner upper face for defining a substantially disk-like space for enclosing the impeller. A groove is formed in the inner lower face, and another groove is formed in the inner upper face. The pair of the grooves extends circumferentially in an area facing the recesses of the impeller from an upstream end to a downstream end along the direction of rotation of the impeller. The recesses in the upper face of the impeller and the groove in the inner lower face of the pump casing form a fuel pressurizing passage, and the recesses in the lower face of the impeller and the groove in the inner upper face of the pump casing form another fuel pressurizing passage.

The pump casing is provided with an intake passage for communicating an exterior of the pump casing to the upstream end of the pressurizing passages and a discharge passage for communicating the downstream end of the pressurizing passage to the exterior of the pump casing.

When the impeller rotates, the fuel is sucked into the upstream end of the fuel pressuring passages from the exterior of the pump casing via the intake passage, the sucked fuel is pressurized as it flows in the circumference direction through the fuel pressuring passages, and the pressurized fuel is delivered from the downstream end of the pressurizing passage to the exterior of the pump casing via the discharge passage.

A side feed pump has been developed in which the intake passage extends within a rotating face of the impeller. In the side feed pump, the intake passage extends along a radius of the pump casing and the impeller. A bottom feed pump has also been developed in which the intake passage extends in a direction orthogonal to the rotating face of the impeller. In the bottom feed pump, the intake passage extends in parallel to the rotational axis of the impeller.

In the side feed pump, fuel can easily be introduced into the fuel pressuring passage at the upper face of the impeller as well as into the fuel pressuring passage at the lower face of the impeller. The fuel pressuring passages at both the upper and lower faces of the impeller are used effectively. In the bottom feed pump, fuel that has been sucked into the fuel pressuring passage at lower face of the impeller via the intake passage must be delivered to the fuel pressuring passage at the upper face of the impeller. It is thus difficult to effectively use the fuel pressuring passage at the upper face of the impeller. Furthermore, in the side feed pump, a fuel filter can be provided at the side of the fuel pump. The overall height of the assembly, in which the fuel filter is attached to the fuel pump, can thus be kept low. The side feed pump has superior pumping performance, and can easily be installed within a shallow fuel tank.

However, the side feed fuel pump has a problem that a tube to which the fuel filter is fixed is not easily formed.

The fuel pump set forth in Japanese Examined Patent Publication 46-33853 does not use the fuel filter. The tube for fixing the fuel filter is not provided at the fuel pump. When the fuel filter is not used, there is a possibility that foreign objects will be sucked into the fuel pump and will damage the fuel pump. The reliability of the fuel pump can thus not be ensured.

The fuel pump set forth in Japanese Unexamined Patent Publication 2000-527677 is utilized within an interior space of a tube-shaped fuel filter. The tube for fixing the fuel filter is not provided at the fuel pump. In this case, a large filter that surrounds the fuel pump is required, and therefore it is not possible to compactly install the assembly of the fuel pump and the fuel filter within a small apace.

FIG. 4 shows a technique for forming a tube to which a fuel filter can be fixed in a side feed pump. This technique was attempted by the present inventor in the process of completing the present invention.

A pump cover 104 and a pump body 204 are joined together to form a pump casing 102. An impeller (not shown) is enclosed within the pump casing 102. An upper fuel pressuring groove 118 that extends along the direction of rotation of the impeller from an upstream end 117 to a downstream end 119 is formed in a lower face of the pump cover 104. Further, an upper intake passage 116 that communicates the upstream end 117 of the upper fuel pressuring groove 118 with an exterior of the pump cover 104 is formed. Also an upper half tube 108 projecting from the pump cover 104 to the exterior of the pump cover 104 is formed. An inner side 112 of the upper half tube 108 joins with the upper intake passage 116. Moreover, a discharge passage 120 that communicates the downstream end 119 of the upper fuel pressuring groove 118 with the exterior of the pump cover 104 is formed in the pump cover 104.

A lower fuel pressuring groove 218 that extends along the direction of rotation of the impeller from an upstream end 217 to a downstream end 219 is formed in an upper face of the pump body 204. Further, a lower intake passage 216 that communicates the upstream end 217 of the lower fuel pressuring groove 218 with an exterior of the pump body 204 is formed. Also a lower half tube 208 projecting from the pump body 204 to the exterior of the pump body 204 is formed. An inner side 212 of the lower half tube 208 joins with the lower intake passage 216.

When the pump cover 104 and the pump body 204 are fitted together to form the pump casing 102, the upper half tube 108 of the pump cover 104 and the lower half tube 208 of the pump body 204 fit together. This forms a tube 108, 208 that, in cross-section, has a unified interior. An intake port 112, 212 is formed in the interior of the tube 108, 208. The intake port 112, 212 communicates the upper intake passage 116 and the lower intake passage 216 with the exterior of the pump casing 102. A fuel filter (not shown) can be fixed to the tube formed by fitting together the upper half tube 108 and the lower half tube 208.

A notch 126 is formed in an overall housing 124 that joins together a pump section and a motor section. The notch 126 corresponds to the location of the tube 108, 208 of the pump casing 102 and allows the tube 108, 208 to extend from the interior side to the exterior side of the housing 124.

When the impeller rotates, the fuel is sucked into the upper pressuring groove 118 and the lower pressuring groove 218 via the fuel filter (not shown), the intake port 112, 212 and the upper intake passage 116 and the lower intake passage 216, is pressurized as it flows along the fuel pressuring grooves 118 and 218, and the pressurized fuel is delivered from the discharge passage 120 to the exterior of the pump casing 102.

SUMMARY OF THE INVENTION

The upper half tube 108 of the pump cover 104 and the lower half tube 208 of the pump body 204 should not have a clearance at their junction from which the fuel could flow, and they should maintain a good sealing performance with an attaching part of the fuel filter. In order to fulfill these requirements, the upper half tube 108 of the pump cover 104 and the lower half tube 208 of the pump body 204 must be processed with extreme precision, and must be fitted together accurately. The pump cover 104 and the pump body 204 must have a determined strength, and are consequently formed so as to be thick. However, this makes it difficult to form the upper half tube 108 or the lower half tube 208 therein with extreme precision. Since the upper half tube 108 of the pump cover 104 and the lower half tube 208 of the pump body 204 cannot easily be processed with extreme precision, manufacture of the pump casing 102 is time-consuming, and manufacturing costs are high.

The present invention has been created in order to overcome the above problems, and presents a fuel pump having a tube that projects from an outer side of a fuel pump. The present invention presents the fuel pump the tube of which can be formed, with extreme precision, both cheaply and in a short time.

In the fuel pump of the present invention, the tube that projects laterally from the fuel pump is formed as a part of an overall housing that jointly encloses both a pump section and a motor section. Inner space of the tube made of the overall housing forms an intake port, and the intake port communicates a side intake passage formed in the pump casing with an exterior of the fuel pump. A fuel filter can be attached to the tube.

The tube formed together with the overall housing allows the fuel to pass smoothly. When the impeller rotates, the fuel is sucked into the intake port within the tube formed of the overall housing. The fuel that has been sucked into the intake port, enters the side intake passage formed in the pump casing, and is introduced into the fuel pressuring passages via the side intake passage.

The overall housing has a function of jointly enclosing the motor section and the pump casing, and is formed of material that has a lesser thickness than the pump casing. The process for forming the tube that projects laterally from the overall housing is easier than the process for forming the tube that projects laterally from the pump casing. Processing time and processing costs can thus be reduced. As a result, the fuel pump can be manufactured with lower cost. Further, since it is easier to process the overall housing, the tube can be processed with greater precision than in the conventional case.

In the present invention, an outer circumference face of the pump casing is substantially cylindrical, and extremely precise processing can thus be performed more easily than in the conventional case. The pump casing can be processed with greater precision.

The present invention is especially useful for a fuel pump that is used within a fuel tank. The fuel in the fuel tank is sucked into the pump casing through the fuel filter attached to the tube, the intake port within the tube, and the side intake passage. Since the fuel filter can be located at the side of the fuel pump, the overall height of the assembly in which the fuel filter is attached to the fuel pump can be kept low. The fuel pump can thus easily be installed within a shallow fuel tank.

In the side feed fuel pump of the present invention, the tube that projects at a location of the side intake passage of the pump casing can be formed together with the overall housing. The process for forming the tube on the overall housing is easier than the process for forming the tube on the pump casing, and processing time can thus be reduced. As a result, the cost of forming the tube and the intake port can be reduced effectively. Further, since processing is easier, the tube can be processed with greater precision than in the conventional case. The sealing performance between the fuel filter and the tube can be improved. Moreover, the outer circumference of the pump casing is substantially cylindrical, and processing can thus be performed easily. The pump casing can consequently be processed with greater precision.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a fuel pump of a first embodiment.

FIG. 2 is a diagonal view of a pump casing and an overall housing of the first embodiment.

FIG. 3 is a cross-sectional view of a pump section and an overall housing of a second embodiment.

FIG. 4 is a diagonal view of a pump casing and an overall housing of a fuel pump that the inventors have tried.

PREFERRED FEATURES TO PRACTICE THE INVENTION

(First Feature) The intake passage of the pump casing is provided in the radial direction of the pump casing. The tube of the overall housing also projects in the radial direction of the pump casing. The intake port and the intake passage are aligned along the same straight line.

(Second Feature) The intake port and the intake passage have an identical cross-sectional shape.

(Third Feature) The intake port and the intake passage have an identical cross-sectional shape, and the intake port and the intake passage are aligned along the same straight line. The fuel that is sucked into the intake hole of the tube flows to the pressuring passages within the pump casing via the intake passage without impediment.

(Fourth Feature) The side intake passage communicates both the fuel pressuring passage at the upper face of the impeller and the fuel pressuring passage at the lower face of the impeller with the exterior of the pump casing.

Preferred Embodiments

Embodiment 1

An embodiment of the present invention is described in detail with reference to FIGS. 1 and 2. A fuel pump of the present embodiment is utilized within a fuel tank of a motor vehicle and is utilized for supplying fuel within the fuel tank to an engine of the motor vehicle.

FIG. 1 is a cross-sectional view of a fuel pump 2 of the present embodiment. FIG. 2 is a diagonal view of a portion of a pump casing and an overall housing 18.

The fuel pump 2 is composed of a pump section 4 and a motor section 20 for driving the pump section 4. The pump section 4 and the motor section 20 are unified by being jointly enclosed within the overall housing 18 that is substantially cylindrical.

The motor section 20 has a direct current motor provided with brushes 32, a rotor 30 and two permanent magnets 28 a and 28 b. The rotor 30 is provided with a motor shaft 22, a commutator 26, a laminated iron core 24, and coils (not shown) wound around the laminated iron core 24. The permanent magnets 28 a and 28 b are fixed along an inner circumference of the overall housing 18. The rotor 30 is provided to the interior of the magnets 28 a and 28 b. The motor shaft 22 passes through the center of the rotor 30. A lower end of the motor shaft 22 is inserted into the pump section 4 and can transmit the rotation of the motor section 20 to the pump section 4. An upper end of the motor shaft 22 is supported, via a bearing 36, on a motor cover 38 attached to an upper end portion of the overall housing 18.

A terminal (not shown) is provided in the motor cover 38, and supplies electricity to the motor section 20. The current that is supplied via the terminal flows the brush 32, the commutator 26 and the coils wound around the laminated iron core 24. The brush 32 and the commutator 26 select the coils that electricity flows. Torque of the rotor 30 is generated within a magnetic field formed by the permanent magnets 28 a and 28 b, and the rotor 30 rotates at high speed.

The pump section 4 is provided with a pump casing 10 and an impeller 12. The impeller 12 is formed in a substantially disk-like shape and has a plurality of recesses 13 formed in an upper face and a plurality of recesses 14 formed in a lower face. The recesses 13 and 14 are formed in an area extending circumferentially at a certain distance from its outer periphery. These recesses 13 and 14 are repeated in the circumference direction. A base portion of each of the recesses 13 at the upper face and a base portion of each of the recesses 14 at the lower face communicate via a through groove 16. Vanes are formed between adjoining recesses.

A lower end portion of the motor shaft 22 fits into the center of the impeller 12, and the motor shaft 22 and the impeller 12 rotate at the same rotational speed.

As shown in FIGS. 1 and 2, the pump casing 10 is formed by joining together a pump cover 6 and a pump body 8, and the impeller 12 is enclosed therein. An upper fuel pressuring groove 51 that extends along the direction of rotation of the impeller 12 from an upstream end 41 to a downstream end 43 is formed in a lower face of the pump cover 6. Further, an upper side intake passage 48 that communicates the upstream end 41 of the upper fuel pressuring groove 51 with an exterior of the pump cover 10 is formed. The upper side intake passage 48 extends in the radial direction of the impeller 12 and the pump casing 10. Moreover, a discharge passage 52 that communicates the downstream end 43 of the upper fuel pressuring groove 51 with the exterior of the pump casing 10 is formed in the pump cover 6. The discharge passage 52 has an opening at an upper part of the pump cover 6, and communicates with a fuel passage formed between the permanent magnets 28 a and 28 b of the motor section 20. A circumference wall 7 of the pump cover 6 has a face 7 a that faces an outer circumference face of the impeller 12. The upper side intake passage 48 passes through the circumference wall 7.

A lower fuel pressuring groove 50 that extends along the direction of rotation of the impeller 12 from an upstream end 45 to a downstream end 47 is formed in an upper face of the pump body 8. Further, a lower side intake passage 49 that communicates the upstream end 45 of the lower fuel pressuring groove 50 with an exterior of the pump casing 10 is formed. The lower side intake passage 49 extends in the radial direction of the impeller 12 and the pump casing 10.

The pump cover 6 and the pump body 8 are fitted together to form the pump casing 10. The pump casing 10 has an inner lower face and an inner upper face for defining a substantially disk-like space for enclosing the impeller 12. The groove 51 is formed in the inner lower face, and another groove 50 is formed in the inner upper face. The pair of the grooves 50, 51 extends circumferentially in an area facing the recesses 13, 14 of the impeller 12 from the upstream end 41, 45 to the downstream end 43, 47 along the direction of rotation of the impeller 12. The recesses 13 in the upper face of the impeller 12 and the groove 51 in the inner lower face of the pump casing 10 form the upper fuel pressurizing passage, and the recesses 14 in the lower face of the impeller 12 and the groove 50 in the inner upper face of the pump casing 10 form the lower fuel pressurizing passage. The pump casing 10 is provided with the upper intake passage 48 for communicating the exterior of the pump casing 10 with the upstream end 41 of the upper pressurizing passage 51 and the lower intake passage 49 for communicating the exterior of the pump casing 10 with the upstream end 45 of the lower pressurizing passage 50. The upper intake passage 48 and the lower intake passage 49 form a side intake passage 53 when the pump cover 6 and the pump body 8 are fitted together to form the pump casing 10.

The pump cover 6 and the pump body 8 are formed by die casting metal, and have sufficient strength that they do not change shape even when the pressure is applied in the fuel pressuring grooves 50 and 51. The side intake passage 53, the fuel pressuring grooves 50 and 51, the discharge passage 52, and the inner circumference face 7 a that faces the outer circumference face of the impeller 12 are each processed so as to be shaped with extremely high precision.

The lower end of the motor shaft 22 is supported, via a bearing 54, by the pump casing 10.

The substantially cylindrical overall housing 18 is formed from metal, and has a tube 42 that projects to the exterior. The overall housing 18 with the tube 42 is formed by pressing a metal plate. The plate thickness of the housing 18 is less than that of the pump casing 10, and the tube 42 can be formed easily, and with high precision, by pressing the metal plate. The tube 42 is formed at a location facing the side intake passage 53 of the pump casing 10 that is enclosed within the overall housing 18. The tube 42 extends in the same direction as the direction in which the side intake passage 53 extends. They extend along the radial direction of the impeller 12 and the pump casing 10. A tip of the tube 42 is open and forms an intake hole 44. The interior of the tube 42 forms a side intake port 46. The cross-sectional shape of the side intake port 46 is processed to be identical with the cross-sectional shape of the side intake passage 53 of the pump casing 10.

The motor section 20 and the pump section 4 are enclosed within the overall housing 18. The overall housing 18 and the pump section 4 are positioned so that the central axis of the tube 42 of the overall housing 18 is identical with the central axis of the side intake passage 53 of the pump casing 10. A lower end of the overall housing 18 is crimped along the outer circumference of the pump body 8. The pump section 4 is fixed to the overall housing 18, so that the intake hole 44, the side intake port 46, and the side intake passage 53 are aligned on the same straight line.

A fuel filter 72 can be attached to the tube 42. An attachment tube 70 is formed on the fuel filter 72. Putting the attachment tube 70 on the tube 42 fixes the fuel filter 72 to the fuel pump 2. The shape of the tube 42 can be processed with extremely high precision so that it corresponds with the shape of the attachment tube 70 at the filter side. The filter 72 can be attached easily by making it thin walled and with a small outer diameter.

The fuel pump 2 is utilized when it is located in a base portion of a fuel tank. When the impeller 12 rotates due to the rotation of the motor section 20, fuel that has been filtered by the filter 72 enters the fuel pump 2 from the intake hole 44. The fuel passes the side intake port 46 and the side intake passage 53 and enters the fuel pressuring passages 50 and 51, and is pressurized as it flows in the circumference direction along these fuel pressuring passages 50 and 51. The pressurized fuel passes through the discharge passage 52, passes through the fuel passage formed between the permanent magnets 28 a and 28 b, passes through a discharge port 56 formed in an upper portion of the motor section 20, then is delivered to the exterior of the fuel pump 2 from a discharge hole 34.

The intake hole 44, the side intake port 46, and the side intake passage 53 have an approximately identical cross-sectional shape, and they are aligned on the same straight line. Consequently, the fuel sucked into the intake hole 44 flows straight along the side intake port 46 and the side intake passage 53 into the fuel pressuring passages 51 and 50. The fuel flows smoothly without impediment and pumping performance is improved.

The fuel pump 2 of the present embodiment is provided with the tube 42 that is formed of the overall housing by pressing. The tip of the tube 42 has the opening that forms the intake hole 44, the interior of the tube 42 forms the side intake port 46, and the side intake port 46 joins with the side intake passage 53 of the pump casing 10. The tube 42 can be formed with high precision and within a short time by pressing. The process of forming the tube 42 on the overall housing 18 is easier than the process of die casting an upper half tube and a lower half tube on the pump cover and the pump body respectively. Consequently, the tube 42 can be formed in a shorter time and more cheaply than in the conventional case.

Further, since the overall housing 18 is easily processed, the shape of the tube 42 can be processed with greater precision than in the conventional case, and the tube 42 can be processed to have a shape that allows the filter to be attached easily, or to have a shape that improves the seal between the tube 42 and the fuel filter 72.

Moreover, in the present embodiment, the outer shape of the pump cover 6 and the pump body 8 is substantially cylindrical. It is thus easy to process the pump cover 6 and the pump body 8. Further, the inner circumference face 7 a that faces the outer peripheral surface of the impeller 12, as well as other components, can be processed with greater precision.

In the present embodiment, a direct current motor having a brush is used. However, other types of motor, such as a brushless motor, etc., can be used. Further, the overall housing 18 and the pump section 4 can be fixed together by a method other than crimping, such as press fitting or bonding.

Embodiment 2

FIG. 3 shows a portion of the pump section 4 and an overall housing 62 of a fuel pump 60 of the present embodiment. Components identical with those of the first embodiment have the same reference numbers assigned thereto and an explanation thereof is omitted.

In the overall housing 62 of the present embodiment, a tube 64 is bonded to a cylindrical section 66 of the overall housing 62. The cylindrical section 66 jointly encloses the pump section 4 and the motor section 20. An opening is formed in the cylindrical section 66 at a location facing the side intake passage 53 of the pump casing 10 that is enclosed within the cylindrical section 66. The tube 64 is bonded with extreme precision to the opening of the cylindrical section 66. The cylindrical section 66 and the tube 64 can be formed of, for example, the same type of metal. Furthermore, the cylindrical section 66 and the tube 64 can be formed of differing materials as long as sufficient adhesiveness can be obtained.

The tube 64 of the overall housing 62 of the present embodiment can be processed in advance into the desired shape, and then bonded to the cylindrical section 66. For example, the tube 64 can be processed such that its plate thickness gradually decreases towards the intake hole 44, so that the inner diameter remains constant while the outer diameter gradually decreases. The tube 64 thus has a shape to which the fuel filter can be attached easily. Further, the outer side of the tube 64 can be processed with extreme precision so as to have an exact shape corresponding to the shape of the attachment position of the fuel filter. The sealing performance between the tube 64 and the fuel filter can thus be improved. In whichever case, it is considerably easier to process the tube 64 with extreme precision when it is a single unit than to do so for a tube that is provided on the pump cover 6 and the pump body 8. Even if it requires time and labor to bond the tube 64 to the cylindrical section 66 precisely, processing costs for the entire fuel pump 60 are still lower than for the conventional example.

Embodiment 3

In the present embodiment, resin is used to form an overall housing. The main portion of the overall housing and the tube to which the fuel filter is fitted is molded integrally by resin. A fuel pump of the present embodiment has the same shape as the fuel pump of the first embodiment shown in FIG. 1.

Resin can be molded more easily than metal into complicated shapes. The process which uses resin to form the overall housing with the tube is thus considerably easier than the conventional process in which the upper tube and lower tube are molded on the pump cover and the pump body. A fuel pump with a side tube can be obtained in a shorter time and more cheaply than in the conventional case.

Specific examples of embodiments of the present invention have been described in detail above, but these merely illustrate some possibilities of the invention and do not restrict the claims thereof. The art set forth in the claims includes various transformations and modifications to the specific examples set forth above.

Furthermore, the technical elements disclosed in the present specification or figures may be utilized to simultaneously realize a plurality of aims or to realize one of these aims. 

1. A fuel pump comprising: a pump section comprising a pump casing and an impeller enclosed within the pump casing; a motor section for rotating the impeller; and an overall housing for jointly enclosing the pump section and the motor section, the overall housing comprising a cylindrical main body and a tube projecting laterally from the cylindrical main body, wherein: the impeller is formed in a substantially disk-like shape, a plurality of recesses is formed at an upper face and a lower face of the impeller along an outer peripheral region of the impeller, a pair of grooves for forming fuel pressuring passages with the plurality of recesses of the impeller is formed in inner faces of the pump casing, the pair of the grooves extending from an upstream end to a downstream end along the direction of rotation of the impeller, a side intake passage is formed along a radius direction of the pump casing for communicating an exterior of the pump casing with the upstream end of the fuel pressuring passages, a discharge passage is formed for communicating the downstream end of the fuel pressuring passage with the exterior of the pump casing, and an inner space of the tube of the overall housing communicates with the side intake passage formed in the pump casing.
 2. A fuel pump as defined in claim 1 further comprising a fuel filter, wherein the fuel filter is mounted on the tube.
 3. A fuel pump as defined in claim 1, wherein the cylindrical main body and the tube are integrally formed of metal plate.
 4. A fuel pump as defined in claim 1, wherein the cylindrical main body and the tube are integrally molded by resin material.
 5. A fuel pump as defined in claim 1, wherein the cylindrical main body and the tube are formed independently and bonded together. 